Field of the Invention
The present invention relates to an imprint apparatus that molds an uncured resin on a substrate using a mold to form a resin pattern on the substrate, and an article manufacturing method using the same.
Description of the Related Art
As the demand for microfabrication of semiconductor devices increases, not only a conventional photolithography technique but also a microfabrication technique in which an uncured resin on a substrate is molded by a mold to thereby form a resin pattern on the substrate have attracted attention. This technique is also referred to as an “imprint technique”, by which a fine structure with dimensions of a few nanometers can be formed on the substrate. One example of imprint techniques includes a photo-curing method. An imprint apparatus employing the photo-curing method firstly applies an ultraviolet curable resin (imprint resin, photocurable resin) to the shot area (imprint area) on the substrate (wafer). Next, the resin (uncured resin) is molded by a mold. After the ultraviolet curable resin is irradiated with ultraviolet light for curing, the cured resin is released from the mold, whereby a resin pattern is formed on the substrate.
On the other hand, since the imprint apparatus brings the mold into contact with the substrate, the cured resin may be released from the substrate to thereby attach to the mold, or a defect may occur in the mold due to being pulled by the cured resin. When a foreign matter is attached to the mold or a defect is present on the mold, a desired resin pattern cannot be formed, which is undesirable in terms of production yield. Accordingly, Japanese Patent Laid-Open No. 2007-523492 discloses a method for determining a mold abnormality by measuring the characteristics of a film formed on a substrate.
However, although the method disclosed in Japanese Patent Laid-Open No. 2007-523492 measures the characteristics of a film formed on a substrate, an abnormality in the characteristics of a film may also occur due to a foreign matter on a substrate or a defect in a mold. Consequently, the method may determine that the mold has an abnormality even if no abnormality actually exists in the mold. Therefore, even if no abnormality actually exists in the mold, the mold may need to be removed from the imprint apparatus to perform an inspection and washing of the removed mold.